The collection and processing of seismic data for the purpose of identifying the source of seismic activity has traditionally involved the use of arrays of sensors capable of measuring seismic activity over a distributed area. Upon collecting seismic data in multiple geographically distinct locations, various types of array signal processing techniques have been utilized to extract information about seismic wave properties, which can help determine the likely location of the seismic source. From a deployment and maintenance perspective, the use of a distributed sensor network for the measurement of seismic data often requires the placement, calibration and synchronization of each sensor in the distributed network. From a signal processing perspective, the use of data collected from a distributed sensor network requires taking into account that properties of the collected seismic signals associated with a single seismic source, such as wave polarization, phase and frequency content, typically vary between sensors in the distributed network.
Existing techniques for the processing of seismic signal data typically utilize band-passed time-domain approaches when extracting information about seismic wave polarization. The use of strictly time-domain approaches for extracting seismic wave polarization typically works well for processing signals received from distant seismic sources where seismic waves of different polarizations, which normally travel at different speeds, can separate sufficiently in time prior to arrival at a particular seismic sensor in the network. When attempts are made to extract wave polarization information from the temporal signals of waves emitted from nearby sources having different polarizations that have not separated sufficiently in time, these polarization extraction methods normally become ill-posed problems. Attempts to determine the direction and location of a seismic source using these methods typically return poor estimates. Existing techniques for processing seismic signal data often use of frequency dependent time windows, such as using a larger time window for lower frequency signals, which suffer from inadequate separation of wave polarization components for nearby seismic sources.